status and future of cint

Status and Future of CINT

Reflex as Reflection DatabaseObject-Oriented CINT

Multi-Threading

Masaharu Goto, Agilent • Philippe Canal, Fermilab • Stefan Roiser, CERN

Paul Russo, Fermilab • Axel Naumann*, CERN(*) 100% CINT

2007-03-26 Axel Naumann • ROOT 2007 2

Status and Future of CINTWhat is it? How does ROOT rely on it?CINT's current statusCINT and Reflex: the new CINT7CINT's future:

– Dictionary developments– Object oriented design– Multi-threading support


What is CINT?• Reflection data manager• Dictionary generator• C++ Parser• Code and library manager• Interpreter• Byte-code compilerStarted in 1991 by Masaharu Goto, originally

in C>300k real LOC (excluding comments / empty

lines)ROOT is major "customer" of CINT


What is CINT? ReflectionCINT manages reflection data (type

information):1. Which types are defined?

Use case: THtml generates doc for all known classes

root [0] THtml hroot [1] h.MakeAll(kTRUE)... 346 htmldoc/TAxis.html 345 htmldoc/TBaseClass.html 344 htmldoc/TBenchmark.html 343 htmldoc/TBits.html 342 htmldoc/TBox.html 341 htmldoc/TBrowser.html 340 htmldoc/TBtree.html 339 htmldoc/TBuffer.html...



information):2. Which members do they have?3. Where are they? (Member offset from

object address)

Use case: I/O writes all members to fileroot [0] TH1::Class()->GetStreamerInfo()->ls()StreamerInfo for class: TH1, version=5... Short_t fBarOffset offset=656 Short_t fBarWidth offset=658 Double_t fEntries offset=664 Double_t fTsumw offset=672 Double_t fTsumw2 offset=680



information):4. Which functions does TNeuron have?

Use case: function lookup in interpreter

root [0] TNeuron neuronroot [1] neuron.MoreCoffee()Error: Can't call TNeuron::MoreCoffee()



information):5. Call a function

Use case: Signal / Slot mechanism in GUI,e.g. sort TBrowser entries by name if name column header is clicked

Connect("Clicked()", "TRootBrowser", fBrowser, Form("SetSortMode(=%d)", kViewArrangeByName));



information):1. Which types are defined? 2. Which members do they have?3. Where are they?4. Which functions does TNeuron have?5. Call a function


What Is CINT?• Reflection data manager• Dictionary generator• C++ Parser• Code and library manager• Interpreter

ROOT's dictionary generator rootcint is based on CINT(genreflex+GCCXML is an alternative)



CINT remembers which macros, libraries were loaded; can re-parse for template instantiations



ROOT prompt.x Macro.CgROOT->ProcessLine(...)


Current StatusMajor developments since last workshop:• Many limitations removed, e.g. concerning

array vs. scalar, auto-loading• Many new features, e.g. AMD64, MS

VisualC++ 2005 support• Reduced memory footprint (-10MB when

running ROOT’s benchmarks.C)• New build system both for CINT itself

(configure) and ROOT’s CINT (cintdlls-Makefile)

• Bug fixes

CINT, ReflexReflex: package to store reflection (=type info)

dataClean C++ API: Type, Scope, Member, e.g. Type::GetDeclaringScope()Scope::SubTypes_Begin()Member::GetType()

To replace CINT’s C structs:• Easier to maintain due to grouping of

functionality (object oriented database), access control, etc

• Fully dynamic, thus smaller memory footprint2007-03-26 Axel Naumann • ROOT 2007 13

CINT + Reflex = CINT7Needs (more than expected) changes:• in CINT, e.g. due to non-modular code• in Reflex, because CINT is a

challenging user (unloading of macros, delayed dictionary initialization, etc)

Preview (30% done) in $ROOTSYS/cint7Work in progress, parallel to

maintenance of CINT5/6Will become default once stable


CINT’s FutureDetailed plan of work:


1. finish CINT7 (Reflex)2. minimize dictionaries (direct lib calls,

dict.root)3. on-the-fly dictionaries (template dicts)4. object-oriented CINT (class

G__Interpreter)5. multi-threading support6. byte-code compiler (loop, scoping

problems)

Dictionary SizeDictionary mainly consists of• call wrappers: translate string "TObject::GetName()" to function call

• Function calls to setup dictionary: add "TObject", add its function "GetName()" etc

• Public re-definition of classes to inspect their (otherwise private) members





problems)








problems)

Extract address of "TObject::GetName()" fromlibrary, forward calls directly to that address








problems

Extract address of "TObject::GetName()" fromlibrary, forward calls directly to that addressStore dictionary data (Reflex objects) in ROOT file, ROOT I/O instead of compiled dictionary








problems

Extract address of "TObject::GetName()" fromlibrary, forward calls directly to that addressStore dictionary data (Reflex objects) in ROOT file, ROOT I/O instead of compiled dictionary

Calculate member inspection data on the fly orexamine (compiler dependent) memory layout

On-Demand DictionaryCurrently: dictionaries for all typesOn-demand: automatically generate and

cache only needed dictionariesOn-demand dictionary example:1.access MyClass<int> but no dictionary yet2.automatically parse MyClass's header3.create dictionary for MyClass<int>4.compile (ACLiC) / load dictionaryGreat for templates: no 100 dicts for 100

template specializations "just in case"2007-03-26 Axel Naumann • ROOT 2007 20




problems

Object-Oriented CINTFor ease of maintenance:Refactor code to convert current C-based

to object oriented designStarted planning of new layout:• interpreter• parser• code manager• dictionary database: Reflex

• dictionary generator• byte-code compiler





problems)

Multi-Threading SupportFor ease of maintenance and thread safety:Refactor code to convert current C-based

to object oriented designStarted planning of new layout:• interpreter: can have multiple per thread• parser: one for each interpreter• code manager: libraries / macros• dictionary database: Reflex (+ thread

safety); libraries / macros• dictionary generator: "static"• byte-code compiler: "static"





problems)

1/process: shared libs,1/interpreter: macros

Byte-Code CompilerByte-code:

custom format for efficient execution of macros

Byte-code compiler: converts macros into byte-code, optimizes it

Problems with scope resolution, loops; difficult to maintain

Status: re-implementation by Masa (CINT6)





problems)

Summary• CINT amazingly stable: very few

changes needed, virtually no API changes

• Well maintained• Shortcomings known, remedy: long list

of planned improvements

Development plans are long scale,with continuous flow of improvements

Benefits arrive on a regular bases!2007-03-26 Axel Naumann • ROOT 2007 24

status and future of cint

Documents

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morecoffeeaxel naumann

functionaxel naumann

fermilab axel naumann

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